Mechanical warewashing machines have been common in the institutional and household environments for many years. Such automatic warewashing machines clean dishes using two or more cycles which can include initially a wash cycle followed by a rinse cycle, but may also utilize soak, pre-wash, scrape, sanitizing, drying, and additional wash cycles. Rinse agents are conventionally used in warewashing applications to promote drying and to prevent the formation of spots.
Rinse agents may also be used in healthcare environments, typically for cleaning a medical cart, cage, instrument, or device. Typically, cleaning a medical cart, cage, instrument, or device includes contacting the medical cart, cage, instrument, or device with an aqueous cleaning composition and, rinsing or contacting the same with a rinse solution comprising a dissolved rinse aid. The method can also involve antimicrobial treatment of the medical cart, cage, instrument, or device by contacting with an aqueous antimicrobial composition formed by dissolving or suspending a solid antimicrobial composition, preferably a solid quaternary ammonium or solid halogen antimicrobial composition.
In either household, institutional, or healthcare environments, rinse agents to reduce the formation of spotting have been, commonly been added to water to form an aqueous rinse that is sprayed on the hard surfaces after cleaning is complete. The precise mechanism through which rinse agents work is not established. One theory holds that the surfactant in the rinse agent is absorbed on the surface at temperatures at or above its cloud point, and thereby reduces the solid-liquid interfacial energy and contact angle. This leads to the formation of a continuous sheet which drains evenly from the surface and minimizes the formation of spots. Generally, high foaming surfactants have cloud points above the temperature of the rinse water, and, according to this theory, would not promote sheet formation, thereby resulting in spots. Moreover, high foaming materials are known to interfere with the operation of warewashing machines.
A number of rinse aids are currently known, each having certain advantages and disadvantages. There is an ongoing need for alternative rinse aid compositions, especially alternative rinse aid compositions that are environmentally friendly (e.g., biodegradable), non-corrosive to metal, can handle high total dissolved solids, can handle high water hardness and are easily manufactured as solids.